My thanks for the info....
I went back to the place I bought it .. they confirmed the existence of the second hexwrench - it's tiny and was missing from the box (or got lost at dealers - because I know I looked at the box and all parts, discussed it with salesperson, and read the manual - which has nothing about it being a different wrench) BUT.. good news is that they gave me one from a new unsold one....
Came home.. it fits and works... have not shot with it yet but the adjustment I believe was needed was easy.... will know for sure next time out....
Problem resolved ...Thanks...